Web ServicesWeb services are open standard (XML, SOAP, HTTP etc.) based Web applications that interact with other web applications for the purpose of exchanging data.Web Services can convert your existing applications into Web-applications.

What are Web Services?

• A web service is any piece of software that makes itself available over the internet and uses a standardized XML messaging system. XML is used to encode all communications to a web service. For example, a client invokes a web service by sending an XML message, then waits for a corresponding XML response. As all communication is in XML, web services are not dependent to any one operating system or programming language--Java can talk with Perl; Windows applications can talk with Unix applications.

• Web services are self-contained, modular, distributed, dynamic applications that can be described, published, located, or invoked over the network to create products, processes, and supply chains. These applications can be local, distributed, or web-based. Web services are built on top of open standards such as TCP/IP, HTTP, Java, HTML, and XML.

• Web services are XML-based information exchange systems that use the Internet for direct application-to-application interaction. These systems can include programs, objects, messages, or documents.

• A web service is a collection of open protocols and standards used for exchanging data between applications or systems. Software applications written in various programming languages and running on various platforms can use web services to exchange data over computer networks like the Internet in a manner similar to inter-process communication on a single computer. This interoperability (e.g., between Java and Python, or Windows and Linux applications) is due to the use of open standards

• A web service is a collection of open protocols and standards used for exchanging data between applications or systems. Software applications written in various programming languages and running on various platforms can use web services to exchange data over computer networks like the Internet in a manner similar to inter-process communication on a single computer. This interoperability (e.g., between Java and Python, or Windows and Linux applications) is due to the use of open standards

SOAP

• SOAP was originally part of the specification that included the Web Services Description Language (WSDL) and Universal Description, Discovery, and Integration (UDDI). It is used now without WSDL and UDDI. Instead of the discovery process described in the History of the Web Services Specification section below, SOAP messages are hard-coded or genereated without the use of a repository. The interaction is illustrated in the figure below. More on

Components of Web Services

• The basic web services platform is XML + HTTP. All the standard web services work using the following components

• SOAP (Simple Object Access Protocol)• UDDI (Universal Description, Discovery and Integration)• WSDL (Web Services Description Language)

How Does a Web Service Work?

• A web service enables communication among various applications by using open standards such as HTML, XML, WSDL, and SOAP. A web service takes the help of:

• XML to tag the data• SOAP to transfer a message• WSDL to describe the availability of service.• You can build a Java-based web service on Solaris that is

accessible from your Visual Basic program that runs on Windows.

Web Services Description Language.

Universal Description, Discovery, and Integration (UDDI)

• The repository shown in the above figure could be a UDDI registry. The UDDI registry was intended to eventually serve as a means of "discovering" Web Services described using WSDL. The idea is that the UDDI registry can be searched in various ways to obtain contact information and the Web Services available for various organizations. How much "discovery" was ever used is open to discussion. Nevertheless, even without the discovery portion, the UDDI registry is a way to keep up-to-date on the Web Services your organization currently uses. It can be used at design time and with governance.

XML-RPC

• This is the simplest XML-based protocol for exchanging information between computers.

• XML-RPC is a simple protocol that uses XML messages to perform RPCs.

• Requests are encoded in XML and sent via HTTP POST.• XML responses are embedded in the body of the HTTP

response.• XML-RPC is platform-independent.• XML-RPC allows diverse applications to communicate.• A Java client can speak XML-RPC to a Perl server.• XML-RPC is the easiest way to get started with web services.

SOAP

• SOAP is an XML-based protocol for exchanging information between computers.

• SOAP is a communication protocol.• SOAP is for communication between applications.• SOAP is simple and extensible.• SOAP allows you to get around firewalls.• SOAP will be developed as a W3C standard.